Shedding mechanism for a loom



Aug. 18, 1964 .J. 'r. SHORT SHEDDING MECHANISM FOR A LOOM 4 Sheets-Sheet 1 Filed Dec. 27, 1962 m wk MEN

INVENTOR Joe 7. Show Q/JMQM ATTORNEYS J. T. SHORT, 3,144,883

SHEDDING MECHANISM FOR A LOOM Aug. 18, 1964 Filed Dec. 27, 1962 4 Sheets-Sheet 2 INVENTOR Joe 7. Shara? A ORNEYS Aug. 18, 1964 J. T. SHORT 3,144,883

SHEDDING MECHANISM FOR A LOOM Filed Dec. 27, 1962 4 Sheets-Sheet 3 u :1 5 x i PRESSURE RETURN INVENTOR Joe I Shari- TTORNEYS United States Patent 3,144,883 Sl-EDDING MECHANISM FOR A LOOM Joe T. Short, West Point, Ga., assignor to Callaway Mills Company, La Grange, Ga., a corporation of Georgia Filed Dec. 27, 1962, Ser. No. 248,183 11 Claims. (Cl. 139-55) The present invention relates to a hydraulically operated shedding mechanism for a loom. The shedding mechanism has particular utility for use on looms intended for weaving heavy fabrics such as are used in conveyor belting and power transmission belting. The utility of the invention is not, however, limited to use in the production of such fabrics.

Suggestions have heretofore been made to utilize a source of power separate from the loom drive to actuate the loom harnesses and to thereby allow more of the power of the loom drive to be used for the feeding of the fabric. Such prior suggestions have, in some instances, involved use of hydraulic or pneumatic devices. The present invention provides a hydraulically operated shedding mechanism having novel control means for assuring harmonic motion of the harnesses in timed relationship with respect to the movements of the other parts of the loom.

An object of the invention is to provide a rugged, dependable and relatively inexpensive hydraulic shedding mechanism for looms, particularly looms intended for the production of heavy fabrics.

Another object of the invention is to provide a hydraulic shedding mechanism with simple control means that can be constructed from readily available components and which will permit exceptionally close control over the movements of the loom harnesses.

The foregoing and other objects and advantages of the invention will be more completely understood by reference to the following description which has reference to the accompanying drawings wherein:

FIGURE 1 is .a somewhat diagrammatic top plan view of the shedding mechanism for operating two of the harnesses of a loom;

FIGURE 2 is a front elevational view of the shedding mechanism;

FIGURE 3 is an enlarged, somewhat diagrammatic longitudinal sectional view of one of the cylinder and piston assemblies utilized in the invention, along with its associated control means, the assembly being shown in a neutral or at rest position; and

FIGURE 4 is an enlarged, fragmentary view of a modified form of control means which may be utilized in conjunction with the cylinder and piston assemblies embodied in the invention.

The shedding mechanism illustrated in the drawings may be briefly described as including a pair of harness supporting shafts which extend at right angles to the planes of the harnesses and from which the harnesses are supported by crank arms. The crank arms which support the harnesses are actuated through mechanical linkages by a double-acting hydraulic cylinder and piston assembly, and a solenoid actuated valve is provided for regulating the flow of hydraulic fluid. A control switch for controlling the valve is secured to the movable element of the piston and cylinder assembly and is actuated by means of a cam driven in synchronism with the loom. The arrangement is such that when a contact of the control switch is actuated by the cam, the control switch actuates the solenoid valve, and the piston and cylinder assembly is operated in response thereto.

A harness has pull rods 11 and 12 secured thereto. The upper end of the pull rod 11 is pivotally connected to an arm 13 of a bell crank 14, which is piovtally mounted on a harness supporting shaft 15. The upper end of the ice pull rod 12 is pivotally secured to an arm 16 of a bell crank 17 which is pivotally mounted on a harness supporting shaft 18. The harness supporting shafts 15 and 18 extend at right angles to the plane of the harness 10 (and to the planes of all other harnesses of the loom) and are suitably supported by supports such as those designated by the reference numerals 19 and 20, as best seen in FIGURE 1.

The bell crank 14 is provided with an arm 21 and bell crank 17 is provided with a similar arm 22. The arms 21 and 22 are connected by a tie bar 23. A crank 24 is fixed on -a rocker shaft 25 which is rotatable in suitable bearings 26. The free end of the crank 24 is pivotally secured to the tie bar by a pivot pin 27. The rocker shaft 25 is parallel to the harness supporting shafts 15 and 18.

Fixed to the rocker shaft 25 is -a crank 28. The free end of the crank 28 is pivotally secured to an end of the piston rod 29. A piston 30 is secured to the other end of the piston rod 29 and is disposed within a cylinder 32. The cylinder 32 has a strut 34 rigidly secured to one end thereof. The strut 34 is pivotally secured to a stationary frame member 36 of the loom by means of a horizontal pivot pin 38 which passes through an upstanding flange 39 fixed to the frame member 36. It will be seen from the elements thus far described that reciprocation of the piston 30 will cause raising and lowering of the harness 10.

The harness 10a is provided with pull rods (not shown) which are similar to the pull rods 11 and 12 and which are connected to hell cranks 14a and 17a. The bell cranks 14a and 17a are similar to the bell cranks 14 and 17 and are pivotally mounted on harness supporting shafts 15 and 18. The upwardly extending arms of the bell cranks 14a and 17a are connected by a tie bar 23a. A rocker shaft 25a is parallel to the rocker shaft 25 and has fixed thereto a crank 24a which is pivoted to the tie bar 23a at 27a. A crank 28a is fixed to the rocker shaft 25a and is pivotally connected to a piston rod 29a which carries a piston disposed in a cylinder 32a of a second cylinder and piston assembly. The cylinder 32a has a strut 34a secured thereto which is pivotally secured to the frame member 36 by means of a horizontal pivot pin 38a passing through an upstanding flange 39a fixed to the frame member 36.

The cylinder and piston assemblies are supplied with hydraulic fluid under pressure through pressure lines 40 from a suitable pump 41. Hydraulic fluid from the cylinder and piston assemblies passes through return lines 42 to a reservoir 44 associated with the pump 41. The pump 41 is provided with a suitable drive motor 45 which is independent of the loom drive. The pump 41 is equipped with a conventional, adjustable pressure control valve which is not shown.

The apparatus for controlling the movements of the piston rod 29 for operating the harness 10 will be described in detail with particular reference to FIGURE 3. It will be understood that the operation of the harness 10a is similar.

A valve, designated generally by the reference numeral 46, includes a valve body 47 that may be carried by the stationary cylinder 32 of the cylinder and piston assembly or may be carried by some other member of the loom. As illustrated in the drawings, the valve body 47 is attached to the cylinder 32 by rigid tubing elements extending from ports 48 and 50 in the valve body 47 to opposite ends of the cylinder 32. These tubing elements are designated by the reference numerals 52 and 54. It will be understood, of course, that the illustrated mounting arrangement for the valve body 47 is exemplary only, and that other suitable arrangements may be employed. When flexible tubing elements are used to connect the valve 3 body 47 to the cylinder 32, the valve body 47 may be mounted on a member that moves relative to the cylinder 32 if desired.

The valve 46 preferably is a standard solenoid actuated closed center four-way valve. It includes a movable valve element 56 having spools 58 and 59,thereon cooperating with the walls of a fluid passageway within the valve body 47 to control the flow of liquid through the ports 48 and 50.

The valve element 56 is shown in its neutral position in FIGURE 3. The valve element 56 is normally urged into this position by a pair of compression springs 60 encircling the end portions of the valve element 56 and acting between the ends of the valve body 47 and washers 64 fixed with respect to the protruding end portions of the valve element 56. In the neutral position of the valve element 56 the spools 58 and 59 cover the ports 48 and 50 to block the flow of fluid to or from the cylinder 32.

Stationary solenoids 66 and 68 surround the end portions of the valve element 56. These solenoids 66 and 68 are energized alternatively by circuit means to be described below. When the solenoid 66 is energized, the valve element 56 moves to the right as viewed in FIG- URE 3, and when the solenoid 68 is energized, the valve element 56 moves to the left.

When the valve element 56 is moved to the left, as viewed in FIGURE 3, the spools 58 and 59 will be moved slightly to the left. This will supply fluid under pressure through line 40 to the valve body 47, outwardly therefrom through the port 48, and into the right end of the cylinder 32 through the tubing 54. This will cause the piston 39 and the piston rod 29 to move to the left as viewed in FIGURE 3, to extend the cylinder and piston assembly. The fluid on the other side of the piston 30 will be forced out of the cylinder 32 and be returned to the valve body 47 through the tubing 52. This fluid is permitted to return to the reservior 44 though the return line 42.

When the valve element 56 is moved to the right, as viewed in FIGURE 3, the flow of the fluid will be into the opposite end of the cylinder 32, and the cylinder and piston assembly will be retracted.

A control switch housing 70 is rigidly mounted on the piston rod 29 by suitable clamp means 71. The control switch housing 70 has mounted thereon a pair of contacts 72 and 73 which are held stationary with respect to the switch housing and are electrically connected with the solenoids 66 and 68 respectively. The control switch further includes a contact 74 which is pivotally mounted at 75 for movement relative to the switch housing 70. The movable contact 74 is connected to a control rod 76 which extends into the control switch housing 70 through an opening 77. It will be seen that movement of the rod 76 will cause the movable contact 74 to engage one or the other of the stationary contacts 72 and 73.

The mechanism for moving the rod 76 can best be seen in FIGURE 2. A cam 80 is fixed on a horizontally disposed cam shaft 82. The cam shaft 82 is driven by a chain 83 which is in turn driven through a gear box 84 by a chain 85 from the loom crank shaft 86. A cam follower 87 is pivoted on a stationary pivot 88 and is provided with a roller 89 which is in rolling contact with the cam 80. A tension spring member 90 maintains the roller 89 in engagement with the cam 80. The upper end of the cam follower 87 is connected to the rod 76 by means of a pivot pin 92.

Movement of the mechanism is initiated by the cam 80. The cam rotates to cause the cam follower 87 to move, and movement of the cam follower 87 will cause the rod 76 to move in one direction or the other.

When the control rod 76 is moved to the left, as viewed in FIGURE 3, the movable contact 74will be brought into engagement with the stationary contact 73. The closing of these contacts will close a circuit to energize the solenoid 68, which in turn will move the valve element 56 to the left. This will permit fluid under. pressure to flow through the port 48 into the tubing 54 and into the right end of the cylinder 32. The fluid entering the cylinder will act on the piston 30 to move the piston rod 29 to its extended position.

As the piston rod 29 moves, it carries with it the control switch housing 70. Therefore, when the control switch housing 70 has advanced tothe left sufficiently to move the contact 73 out of engagement with the movable contact 74, the circuit to the solenoid 68 will be broken, and the valve element 56 will be free to return to its neutral position under the influence of the springs 60. Further movement of the piston and piston rod to the left then can be brought about only by moving the control rod 76 to the left far enough to re-engage the contacts 73 and 74. Thus, it will be seen that the alternate opening and closing of the contacts 73 and 74 will cause the piston and cylinder assembly to extend in a pattern following closely the pattern of the cam 80. Although the action is stepwise in theory, a smooth continuous motion results in actual practice because of the small amount of relative motion required for the making and breaking of the contacts 73 and 74.

The retraction of the cylinder and piston assembly is brought about in a similar manner. In this instance, the movable contact 74 engages the stationary contact 72 for energizing the solenoid 66. This solenoid 66 moves the valve element 56 to the right, as viewed in FIGURE 3, to direct fluid under pressure through the tubing 52 to the left end of the cylinder 32 to retract the piston rod 29.

Although FIGURE 3 shows the contacts 72, 73 and 74 as being spaced substantial distances from each other, it will be understood that, in an actual embodiment of the invention, these contacts may be quite close together. They need be spaced apart only far enough to permit the circuits to be broken in the intended manner. By placing the contacts 72, 73 and 74 close together, it is possible to minimize the lost motion between the beginning of a movement of the control rod 76 in a given direction and the beginning of a corresponding movement of the piston rod 29.

Thesecond harness 10a has operating means similar to the elements which have been described. The piston rod 29a of the cylinder and piston assembly for actuating the harness 10a is somewhat longer than the piston rod 29. In all other respects, the elements for actuating the harness 10a are identicalto those described above in the same reference numerals followed by the suffix a" as used in a corresponding element. It will be understood that a larger number of harnesses and operating means may be used on the loom. The pump 41 can be used to provide hydraulic fluid to the operating means for all harnesses. All of the cams 80 are mounted on the cam shaft 82. All bell cranks corresponding to the bell cranks 14 and 17 may be pivotally mounted on the harness supporting shafts 15 and 18.

The manner in which the harnesses are manipulated may be altered by use of cams of different contours. It is possible to change the angular positions of the cams on the cam shaft or to replace them with cams of different contours. It is thus possible to change the fabric construction or design with a minimum of effort and time expenditure.

The switch means arrangement illustrated in FIGURE 3 affords advantages of structural simplicity. An alternative switch means arrangment illustrated in FIGURE 4 is particularly noteworthy from a safety standpoint.

Whereas, in the FIGURE 3 embodiment, switch actuation is effected by movement of contacts in a direction generally aligned with the axial movement of rod 76, contact movement in the FIGURE 4 arrangement occurs in a direction transverse to the direction of movement of the rod 76.

The FIGURE 4 arrangement includes a housing 100, corresponding to the housing 70 of the FIGURE 3 emrod 29 by means such as clamp means 101.

Housing 100 includes a pair of fixed contacts 102 and 103 corresponding, respectively, to the contacts 72 and 73 of the FIGURE 3 embodiment. As shown in FIG- URE 4, fixed contact 103 is disposed above and spaced from the fixed contact 102. A movable contact 104 corresponding to the contact 74 of the FIGURE 3 embodiment, is pivotally mounted at pivot point 104a. Contact 104 is mounted as shown in FIGURE 4 so as to provide opposed contact surfaces disposed betwee the fixed con tacts 102 and 103. A coil spring 105 engages the upper surface of pivotable contact member 104 and urges contact member 104 into engagement with the upper end of a reciprocable, rod-like follower member 106. Member 106 is mounted in the lower wall of housing 100 so as to be reciprocable in a direction normal to the direction of axial movement of the rod 76. A roller type, cam follower component 107 is carried on the outer end of reciprocable follower member 106 as shown.

Switch actuating cam means are carried by the rod 76 to cooperate with the follower 107 and effect switch actuating reciprocation of the member 106. This cam means is adjustable in nature and comprises a first cam plate 108 mounted on a flattened side of rod 76 in the path of follower 107 and a second cam plate 109 displaced from plate 109, aligned in the plane of plate 109, and also mounted on the flattened side of rod 76. As shown in FIGURE 4, cam plates 108 and 109 may be provided with elongate slots so as to facilitate their positional adjustment on the rod 76 in relation to threaded securing screws 110.

Cam plate 108 includes an upper cam surface 108a which allows the follower 107 to move downwardly sufficiently to cause engagement between contact 102 and 104. Cam plate 107 includes a second camming surface 108k spaced from the plane of surface 108a in a direction toward follower 107. When the follower 107 engages cam surface 108b, the contact 104 is held in an intermediate or neutral position spaced from the contacts 102 and 103.

Cam plate 109 includes a cam surface 109a spaced from the plane of surface 108b in a direction toward follower 107. When follower 107 engages cam surface 109a, the contact 104 is caused to engage contact 103.

An inclined cam surface 1080 disposed between surfaces 108a and 108b provides for the transitional movement of roller 107 between these latter surfaces. Similarly, an inclined cam surface provides for the transitional movement of roller 107 between cam surfaces 10817 and 109a.

As shown in FIGURE 4, surfaces 108a, 10811 and 109a are flat surfaces oriented so as to be perpendicular, i.e. normal, to the axis of reciprocation of member 106 and parallel to the axis of reciprocation of the rod 76.

Inclined cam surface 10% is formed on a portion of cam plate 109 which projects over an adjacent end of cam plate 108. With this arrangement, the relative positions of cam plates 108 and 109 may be varied so as to alter the longitudinal extent of surface 1023b by changing the point where surface 10% intersects an intermediate portion of surface 108b, as well as alter the relative actuating positions of the various cam surfaces, while maintaining general continuity of the cam surfaces 108b, 1091) and 109a.

The manner in which switch actuation is effected by the FIGURE 4 apparatus is self-evident. This illustrated switch arrangement functions as a conventional, single pole, double throw, spring loaded switch, wherein the actuator, i.e. rod 106 and follower component 107, follows the profile of the actuating cams 108 and 109. Engagement of the contacts 103 and 104, as influenced by the cooperation of follower 107 and cam surface 109a, effects the energization of solenoid 68. Engagement of the contact 102 and 104 caused by the cooperation of follower 107 and cam surface 108a effects the energization of solenoid 66.

As will be apparent, the manner in which the switch means illustrated in FIGURE 4 controls a cylinder and piston assembly is identical to the manner in which the switch means illustrated in FIGURE 3 effects this control operation. However, with the FIGURE 4 apparatus, should a failure in the system occur which would cause the rod 76 to move beyond desired movement limits, no possible damage to the switch mechanism could occur. Such abnormal movement of rod 76 would merely cause the cam plates 108 and 109 to move past the transversely yieldable cam follower 107.

The free end of rod 76 may be slideably supported in a bracket portion 111 carried with the housing 100. As illustrated in FIGURE 4, bracket 111 would be spaced sufliciently from cam plates 108 and 109 so as to accommodate the maximum anticipated extent of reciprocation of these cam members.

In addition to the safety feature resulting from the FIG- URE 4 structure, it will also be appreciated that a unique control adjustability is provided. The slideably adjustable nature of the individual cams enables them to be easily adjusted on each individual rod 76 to accommodate to particular control requirements.

It will be understood that in schematically illustrating this invention, no attempt has been made to show conventional insulation that would ordinarily be associated with the various contact elements.

I have illustrated and described what I now consider to be the preferred embodiments of my invention. It will be understood that various modifications may be made without departing from the broader scope of the invention which is defined by the claims.

This application is a continuation-in-part of my copending application Serial No. 133,181, filed August 22, 1961, now abandoned.

Having thus described my invention, I claim:

1. In a loom having a harness, operating means for raising and lowering said harness comprising: a doubleacting cylinder and piston assembly; means securing one element of said assembly to a stationary portion of the loom; a source of fluid under pressure; electrically operated valve means operatively connected to said cylinder and piston assembly; switch means electrically connected to said valve means for actuating said valve means to direct fluid under pressure to said cylinder to cause the other element of said cylinder and piston assembly to move; a cam; means for driving said cam in synchronism with the loom; a cam follower driven by said cam; said switch means including first contact means connected to said cam follower for movement therewith and second contact means connected to said other element of said cylinder and piston assembly for movement therewith; one of said contact means including a first contact element electrically connected to said electrically operated valve for actuating said valve in one. direction and a second contact element electrically connected to said electrically operated valve for actuating said valve in the opposite direction; the other of said contact means being positioned to cooperate alternatively with said first and second contact elements to complete electrical circuits therethrough, the circuit completed upon relative movement between said cam follower and said other element of said cylinder and piston assembly in one direction being effective to condition said valve means so as to cause relative movement between said cam follower and said other element of said cylinder and piston assembly in the opposite direction; and means connecting said assembly to said harness to raise and lower the harness upon reciprocation of said other element of said assembly.

2. In a loom having a harness, operating means for raising and lowering said harness comprising: a doubleacting cylinder and piston assembly; means securing one element of said assembly to a stationary portion of the loom; a source of fluid under pressure; electrically operated valve means operatively connected to said cylinder and piston assembly; switch means electrically connected to said valve means for actuating said valve means to direct fluid under pressure to said cylinder to cause the other element of said cylinder and piston assembly to move; a cam; means for driving said cam in synchronism with the loom; a cam follower following the contour of said cam; said switch means including first contact means connected to said cam follower for movement therewith and second contact means connected to said other element of said cylinder and piston assembly for movement therewith; one of said contact means having a pair of spaced apart contact elements and the other of said contact means having a contact element disposed between said contact elements of said pair; and linkage means connecting said assembly to said harness to raise and lower the harness upon reciprocation of said other element of said assembly.

3. In a loom having a harness, operating means for raising and lowering said harness comprising: a doubleacting cylinder and piston assembly; means securing one element of said assembly to a stationary portion of the loom; a source of fluid under pressure; electrically operated valve means operatively connected to said cylinder and piston assembly; switch means carried by the other of said elements of said assembly for movement therewith and being electrically connected to said valve means for actuating said valve means, said switch means being adapted to actuate said valve means to direct fluid under pressure to said cylinder to cause said other element to move; said switch means being responsive to the movement of said other element for closing said valve; a cam; means for driving said cam in synchronism with the loom; a cam follower following the contour of said cam and connected to said switch for operating the same to cause said other element of said assembly to partake of reciprocating movement corresponding to the contour of said cam; and linkage means connecting said assembly to said harness to raise and lower the harness upon reciprocation of said other element of said assembly.

4. In a loom having a harness, operating means for raising and lowering said harness comprising: a doubleacting cylinder and piston assembly; means securing the cylinder of said assembly to a stationary portion of the loom; a piston rod secured to said piston for movement therewith relative to the cylinder; a source of fluid under pressure; a solenoid actuated valve supported on a stationary portion of the loom; an electric switch carried by the piston rod of said assembly for movement therewith and operatively connected with said valve for actuating said valve, said switch adapted to actuate said valve to direct fluid under pressure to said cylinder to cause said piston andpiston rod to move; said switch beingresponsive to the movement of said piston rod for closing said valve; a cam; means for driving said cam in synchronism with the loom; a cam follower following the contour of said cam and connected to said switch for operatingthe same to cause said piston rod to partake of'reciprocating movement corresponding to the contour of said cam; and link means connecting said assembly to said harness to raise and lower the harness upon reciprocation of said piston rod.

5. In a loom having a harness, operating means for raising and lowering said harness comprising: a doubleacting cylinder and piston assembly; means securing one elementof said assembly to a stationary portion of the loom; a source of fluid under pressure; valve means supported on a stationary portion of the loom; switch means carried by the other of said elements of said assembly for movement therewith and operatively connected with said. valve means for actuating said valve means, said switch means including a pair of spaced contacts and a further contact normally occupying an open position between said pair of contacts and maintaining said valve in a closed position for preventing flow of fluid from said source to said cylinder, said further contact being movable from said open position in one direction toengage a first one of said pair of contacts for actuating said valve to direct fluid under pressure from said source to said cylinder to cause said other element of said assembly to follow the movement of said further contact in said one direction until the extent of said movement moves said first contact from engagement with said further contact and said valve is thereby returned to closed position, said further contact being movable from said open position in the opposite direction to engage a second contact of said pair of contacts for actuating said valve for directing fluid under pressure from said source to said cylinder to cause said other element of said assembly to follow the movement of saidfurther contact in said opposite direction utnil the extent of said movement moves said second contact from engagement with said further contact and said valve is thereby returned to closed position; a cam; means for driving said cam in synchronism with the loom; a cam follower following the contour of said cam and connected to said further contact for moving the same with respect to said other element of said assembly to cause said other element of said assembly to partake of reciprocating movement cor responding to the contour of said cam; and linkage means connecting said assembly to said harness to raise and lower the harness upon reciprocation of said other element of said assembly.

6. In a loom having a harness, operating means for raising and lowering said harness comprising: a doubleacting cylinder and piston assembly; means securing the cylinder of said assembly to a stationary portion of the loom; a source of fluid under pressure; valve means supported on a stationary portion of the loom; a piston rod connected to said piston for movement therewith relative to said cylinder; switch means carried by the piston rod of said assembly for movement therewith and operatively connected with said valve means for actuating said valve means, said switch means including a pair of spaced contacts and a further contact normally occupying an open position between said pair of contacts and maintaining said valve in a closed position for preventing flow of fluid from said source to said cylinder, said further contact being movable from said open position in one direction to engage a first one of said pair of contacts for actuating said valve to direct fluid under pressure from said source to said cylinder to cause said piston rod to follow the movement of said further contact in said one direction until the extent of said movement moves said first contact from engagement with said further contact and said valve is thereby returned to closed position, said further contact being movable from said open position in the opposite direction to engage a second contact of said pair of contacts for actuating said valve for directing fluid under pressure from said source to said cylinder to cause said piston rod to follow the movement of said further contact in said opposite direction until the extent of said movement moves said second contact from engagement with said further contact and said valve is thereby returned to closed position; a cam; means for driving said cam in synchonism with the loom; the cam follower following the contour of said cam and connected to said further contact for moving the same with respect to said piston rod to cause said piston rod to partake of reciprocating movement corresponding to the contour of said cam; and linkage means connecting said assembly to said harness to raise and lower the harness upon reciprocation of said piston rod.

7. An apparatus as described in claim 3 and including: cam means operated by said cam follower for controlling the operation of said switch means, said cam means being mounted for reciprocating movement; and cam follower means carried by said other element of said assembly and adapted to reciprocate normal to the direction of reciprocation of said cam means, said cam follower means being adapted to yieldably engage said cam means and effect the operation of said switch means in response to reciprocation of said cam means.

8. An apparatus as described in claim 7 wherein said cam means comprises: a first cam plate having a first, flat cam surface disposed normal to said follower means, a second cam surface inclined relative to said first cam surface, and a third, fiat cam surface disposed normal to said follower means and lying in a plane spaced from the plane of said first cam surface in a direction toward said follower means; and a second cam plate including a fourth, fiat cam surface disposed normal to said follower means and lying in a plane spaced from the plane of said third cam surface in a direction toward said follower means, and a fifth cam surface inclined to said fourth cam surface and extending between a intermediate portion of said third cam surface, and said fourth cam surface; said cam plates being relatively adjustable in position along the axis of reciprocation of said cam means whereby the position of said fifth cam surface in relation to said third cam surface may be selectively varied.

9. In a loom having a harness, operating means for raising and lowering said harness comprising: a doubleacting cylinder and piston assembly; means securing one element of said assembly to a stationary portion of the loom; a source of hydraulic fluid under pressure; electrically operated valve means operatively connected to said cylinder and piston assembly; switch means carried by the other of said elements of said assembly for movement therewith and being electrically connected to said valve means for actuating said valve means, said switch means being adapted to actuate said valve means to direct fluid under pressure to said cylinder to cause said other element to move; said switch means being responsive to the movement of the said other element for closing said valve; a cam; means for driving said cam in synchronism with the loom; a cam follower following the contour of said cam and operating said switch to cause said other element of said assembly to partake of reciprocating movement corresponding to the contour of said cam; and linkage means connecting said assembly to said harness to raise and lower the harness upon reciprocation of said other element of said assembly.

10. In a loom having a harness and cylinder and piston means for effecting the raising and lowering thereof, the improvement comprising: switch means for controlling the application of pressurized fluid to said cylinder and piston means; cam means mounted for reciprocating movement for controlling the operation of said switch means; and cam follower means adapted to reciprocate normal to the direction of reciprocation, of said cam means, said cam follower means being adapted to yieldably engage said cam means and effect the operation of said switch means in response to reciprocation of said cam means; said cam means including first and second cam plates; said first cam plate having a first fiat cam surface disposed normal to said follower means, a second cam surface inclined relative to said first cam surface, and a third flat cam surface disposed normal to said follower means and lying in a plane spaced from the plane of said first cam surface in a direction toward said follower means; said second cam plate including a fourth fiat cam surface disposed normal to said follower means and lying in a plane spaced from the plane of said third cam surface in a direction toward said follower means, and a fifth cam surface inclined to said fourth cam surface and extending between an intermediate portion of said third cam surface and said fourth cam surface; said cam plates being relatively adjustable in position along the axis of reciprocation of said cam means whereby the position of said fifth cam surface in relation to said third cam surface may be selectively varied.

11. In a loom having a harness and a cylinder and piston assembly including a movable element for etfecting the raising and lowering thereof, the improvement comprising: electrical switch means for controlling the application of pressurized fluid to said cylinder and piston assembly; a cam and follower combination for operating said switch means and including a cam member and a follower member yieldingly engaging said cam member, a first one of said members being carried by the movable element of the cylinder and piston assembly and being mounted for movement in a direction normal to the direction of movement of said movable element, a second one of said members being mounted for movement relative to said movable element of the cylinder and piston assembly in a direction parallel to the direction of movement of said element, one of said members being operatively connected to said switch means; and drive means for reciprocating said second member in timed relation to the operation of the loom.

References Cited in the file of this patent UNITED STATES PATENTS 2,145,977 Foster Feb. 7, 1939 2,177,828 Huck Oct. 31, 1939 2,425,676 Hindle Aug. 12, 1947 2,580,279 Briglia Dec. 25, 1951 2,629,306 Rusconi Feb. 24, 1953 2,782,863 Christy et a1. Feb. 26, 1957 3,001,360 Budzich et al. Sept. 26, 1961 3,042,326 Lamb et al. July 3, 1962 

1. IN A LOOM HAVING A HARNESS, OPERATING MEANS FOR RAISING AND LOWERING SAID HARNESS COMPRISING: A DOUBLEACTING CYLINDER AND PISTON ASSEMBLY; MEANS SECURING ONE ELEMENT OF SAID ASSEMBLY TO A STATIONARY PORTION OF THE LOOM; A SOURCE OF FLUID UNDER PRESSURE; ELECTRICALLY OPERATED VALVE MEANS OPERATIVELY CONNECTED TO SAID CYLINDER AND PISTON ASSEMBLY; SWITCH MEANS ELECTRICALLY CONNECTED TO SAID VALVE MEANS FOR ACTUATING SAID VALVE MEANS TO DIRECT FLUID UNDER PRESSURE TO SAID CYLINDER TO CAUSE THE OTHER ELEMENT OF SAID CYLINDER AND PISTON ASSEMBLY TO MOVE; A CAM; MEANS FOR DRIVING SAID CAM IN SYNCHRONISM WITH THE LOOM; A CAM FOLLOWER DRIVEN BY SAID CAM; SAID SWITCH MEANS INCLUDING FIRST CONTACT MEANS CONNECTED TO SAID CAM FOLLOWER FOR MOVEMENT THEREWITH AND SECOND CONTACT MEANS CONNECTED TO SAID OTHER ELEMENT OF SAID CYLINDER AND PISTON ASSEMBLY FOR MOVEMENT THEREWITH; ONE OF SAID CONTACT MEANS INCLUDING A FIRST CONTACT ELEMENT ELECTRICALLY CONNECTED TO SAID ELECTRICALLY OPERATED 